Virtualization may enable multiple operating systems to run on one physical host computer. The number of virtual machines (VMs) per physical host computer has seen an increase in recent times with the advent of powerful hardware. As hardware becomes even more powerful, higher consolidation ratios of VMs on a host computer may be expected. As higher workloads are being consolidated in a host computer, the advantage a customer/user has may directly be proportional to the workloads and/or the number of applications involved.
In a development and simulation cloud, resource bottlenecks may exist due to VMs running in idle state. While resource limitations have been lifted by technology advances, such as over-commitment of resources like memory, disk and processor cores, certain virtualized applications, such as simulation environments, may still occupy resources when not used for productive work. However, users tend to not suspend their VMs due to various reasons. One is the fact that VMs are managed via a Web GUI, but the interaction with the virtual machines instances occurs mostly via Secure Shell (SSH) or Virtual Network Computing (VNC).
Therefore, in virtualized computer systems it may be desirable in certain circumstances to suspend a virtual machine and resume it at a later time. In order to save resources, for instance, computing power, energy or memory, it may also be advantageous to suspend a virtual machine and resume it at a later time.